자가 형성 ITO 나노 Dot에 의한 A1GaInP-기반 나노 기둥 발광 다이오드에 관한 연구

다국어 초록 (Multilingual Abstract)

The AlGaInP exhibiting a direct band gap from 1.8eV to 2.3eV is an attractive material system for light emitting diodes (LEDs) covering the visible spectrum from the red and yellow/green region. The AlGaInP material can be precisely lattice matched to GaAs substrates without generating much misfit. Due to the small band gap of GaAs substrates, almost light divesting structure Wafer bonding technology has been extensively used for orange-and red-color high-brightness LED application. In LED structure, spontaneous emission is assumed to be isotropic, and approximately half of the light goes toward the substrate. Given the strong interest in the epitaxial quality of AlGaInP-based materials in recent years, the internal quantum efficiency of AlGaInP LEDs has reached near 100%. However, there is still a significant gap between the internal efficiency of LEDs and their external efficiency. The main reason is the difficulty for light to
escape from a high-refractive-index semiconductor into the air. Thus, if high-performance AlGaInP-based LEDs, an to be obtained enhanced the light extraction efficiency is of significance. Wafer bonding technology has been extensively used for orange-and red-color high-brightness LED application. In LED structure, spontaneous emission is assumed to be isotropic, and approximately half of the light goes toward the substrate. Those photons would easily be absorbed if the substrate had a smaller bandgap than the active region. In order to achieve high brightness LED, one can incorporate bottom distributed Bragg reflectors or metal layers into in the LED structure to reflect the light back to the surface and to prevent it from entering the absorbing substrate. Among the various methods ITO(Indium-Tin-Oxide) utilization HCl Chemical Etching Nano ball size mask patterns without lithography process.

목차 (Table of Contents)

• 제1장 서론 1
• 1.1 연구의 배경 1
• 제2장 이론적 배경 5
• 2.1 LED(Light Emitting Diode)의 발광원리 5
• 2.2 LED의 광학적 특성 8
• 2.2.1 광 추출 효율 (Light Extraction Efficiency) 8
• 2.2.2 탈출원뿔(Light escape cone) 10
• 2.2.3 Lambertian Emission Pattern 13
• 2.2.4 2차원 광결정 (2Dimensional Photonic Crystal) 15
• 제3장 실험방법 및 결과 19
• 3.1 Nano Dot 형성 및 pillar 제작 19
• 3.1.1 실험개요 19
• 3.1.2 실험방법 20
• 3.1.3 실험결과 20
• 3.2 Nano pillar 깊이에 따른 N-AlGaInP VLED 광추출효율 향상 연구 23
• 3.2.1 실험개요 23
• 3.2.2 실험방법 24
• 3.2.3 실험결과 27
• 3.3 Nano pillar 두께에 따른 N-AlGaInP VLED 광추출효율 향상 연구 33
• 3.3.1 실험개요 33
• 3.3.2 실험방법 34
• 3.3.3 실험결과 37
• 3.4 Nano pillar 와 Roughness 적용된 N-AlGaInP VLED 광추출효율 변화에 관한 연구 44
• 3.4.1 실험개요 44
• 3.4.2 실험방법 45
• 3.4.3 실험결과 48
• 제4장 결론 52
• 참고문헌 55
• 감사의 글 57